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Biomedical subjects

F Perlík

Publications and source records attributed to F Perlík.

At least 37 records · Page 2Linked to original sources
PubMed1992

Disposition kinetics and concentration-effect relationship of metipranolol in patients with cirrhosis and healthy subjects.

The disposition kinetics and heart rate reducing effect of deacetylmetipranolol (DMP), the active form of the beta-adrenoreceptor blocking agent metipranolol (MP), administered as a single 40 mg oral dose have been compared in 6 patients with cirrhosis and 6 healthy volunteers. The mean maximal DMP concentration was significantly higher and the time to reach the peak level shorter in the patients compared to the healthy subjects. There was also a significantly higher AUC of DMP, a shorter half-life of the rapid phase of the decline in DMP concentrations, a smaller central compartment and lower apparent DMP clearance in patients. A correlation with the albumin level was observed in cirrhotics for individual values of apparent DMP clearance (r = 0.92) and AUC (r = -0.89). The maximal reduction in heart rate was recorded in patients at plasma DMP levels which were already significantly lower than the peak levels. Median inhibitory concentrations (IC50) and maximum possible heart rate reductions (delta HRmax), obtained by fitting individual plots of the plasma DMP concentration-effect relationship to the inhibitory Emax model in the postdistributional phase of DMP disposition were significantly higher in cirrhotics than in healthy subjects. It is conjectured that down-regulation of adrenoreceptors due to chronic sympathetic activation in hepatic cirrhosis contributes to decreased sensitivity to the reduction in heart rate following a single dose of the beta-blocker.

Adult↗
PubMed1992

Binding parameters of phenytoin during monotherapy and polytherapy.

The present in vivo study elucidated the effect of other commonly comedicated drugs on the phenytoin (PHT) Scatchard binding parameters. Specimens of 150 epileptic patients chronically treated with anticonvulsant drugs were analyzed. The results of covariance analysis suggest that phenobarbitone, ethosuximide, diazepam and folic acid do not alter binding of PHT to serum albumin. The contribution of carbamazepine and medazepam to the free fraction of PHT (decrease of about 0.4%) and/or Scatchard binding capacity (increase of about 1/3) is ambiguous and not statistically significant at the p less than 0.05 level. On the contrary, we found a statistically significant decrease of PHT binding in patients comedicated with valproic acid (VPA) and primidone (PRM). The decrease of about 25% in binding capacity evoked an increase of about 1% (VPA), and 1.5% (PRM), respectively in PHT free fraction.

Adult↗
PubMed1991

[Changes in pharmacokinetics of trimecaine in patients with liver cirrhosis].

Trimecaine (Mesocain, Léciva) an analogous preparation to lidocaine is used as a local anaesthetic, antiarrhythmic and spasmolytic preparation. The purpose of the investigation was to assess the fate of trimecaine in nine patients with compensated cirrhosis of the liver. The pharmacokinetics were evaluated after intravenous infusion of trimecaine administered at a rate of 150-200 mg.h-1. Plasma concentrations of the drug evaluated by gas chromatography indicate a marked retardation of trimecaine elimination in patients with liver damage. In the group of patients with cirrhosis of the liver the total clearance of the drug was lower (8.7 +/- 5.0 1.h-1), as compared with the group of patients without liver damage (34.7 +/- 19.4 1.h-1). In patients with cirrhosis of the liver also a multiple reduction of distribution volumes was observed. The results indicate a high hepatic extraction of

Humans↗
PubMed1991

[Binding of phenytoin to serum albumin in vitro and in vivo].

The present paper describes an ultrafiltration method of determination of the concentration of free phenytoin (DPH) in serum and its use for the study of the binding equilibrium phenytoin--albumin. The procedure was employed to determine the binding affinity of serum albumin (a) in a group of healthy volunteers (n = 8) in in vitro conditions, (b) in a group of healthy volunteers (a mixed serum, n = 6) and (c) in a group of patients suffering from epilepsy with fits of the generalized type grand mal (n = 15) in in vivo conditions. The calculation of binding parameters was carried out by the method of nonlinear regression analysis with the use of the one-parameter Scatchard's model of the bond. Binding activity of serum albumin in the volunteers of group (a) was N.Ka = 17,500 l/mol, group (b) N.Ka = 18,700 l/mol, and in patients with epilepsy n.Ka = 19,200 l/mol. The results of covariational analysis demonstrated good agreement in the binding parameters of all three groups under study. The paper also discusses the suitability of the binding model used and the mathematical processing and possible use of the binding parameters measured in in vitro conditions for the estimation of the value of the free fraction of the drug in patients with epilepsy.

Adult↗
PubMed1990

[Possibilities of predicting serum levels of lithium and subsequent correction of its dosage].

The objective of the present work was to evaluate the practicability of several procedures used for prediction of the serum concentration of lithium in a steady state which will make it possible to adjust the dosage in the early period of treatment. The group comprised nine men where prophylactic lithium treatment was indicated on account of maniomelancholy. The authors assessed in each patient the theoretically calculated and actually assessed value of minimal lithium concentrations in a steady state. In all applied predictive methods the predicted values were always higher than the actually assessed lithium concentrations. The least suitable method was that based on individualization of the population average of the velocity constant of elimination. The predictive value of the procedure based on a non-individualized single-point estimate was higher. A statistically significant correlation of predicted and assessed values was provided by the method which, based on two collected samples of lithium serum concentrations, makes it possible to estimate the individual value of the cumulative factor.

Adult↗
PubMed1990

[Atrial natriuretic factor in liver cirrhosis. Relation to hemodynamic parameters].

In 12 patients with cirrhosis of the liver (six with ascites) and six controls the authors made catheterizations of the hepatic veins and portal circulation, assessing concurrently the in cardiac output by thermodilution. The patients with ascitic cirrhosis had, as compared with controls, a significantly higher portohepatic gradient, central venous pressure, mean pressure in the pulmonary artery and also pulmonary capillary wedged pressure and a significantly lower mean arterial pressure and systemic vascular resistance. These patients had also, as compared with controls, a significantly higher concentration of ANF (atrial natriuretic factor) in the pulmonary artery (15.89 +/- 2.26 vs. 8.04 +/- 0.97, p less than 0.01) and in the hepatic vein (7.44 +/- 0.44 vs. 3.91 +/- 0.63, p less than 0.01); the difference between ANF concentrations in the peripheral blood stream was not significant (9.52 +/- 2.46 vs. 5.71 +/- 1.24 n. s.). Patients with ascitic cirrhosis of the liver had a significantly higher calculated cardiac production of ANF than controls (24.36 +/- 3.44 vs. 8.12 +/- 2.9, p less than 0.01); the difference in the splanchnic extraction of ANF between patients with ascitic cirrhosis of the liver (0.46 +/- 0.1) and controls (0.51 +/- 0.06) was not significant. The ANF concentration in the pulmonary artery in patients with cirrhosis of the liver correlated significantly with the central venous pressure (r = 0.677, p = 0.02) and the pressure in the pulmonary artery in a wedged position (r = 0.639, p = 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Natriuretic Factor↗
PubMed1990

[The effect of the method of detecting indocyanine green (HPLC, spectrophotometry) on the determination of pharmacokinetic parameters].

The method of determination of indocyanine green (ICG) in plasma by means of high-performance liquid chromatography (HPLC) is compared with the method of spectrophotometry. A sample for HPLC is purified by deproteination with acetonitrile and the supernatant is directly spread on the column. The internal standard is diazepam. The mobile phase consists of 50% of phosphate buffer pH 6 prepared according to PhBs 4, 47% of acetonitrile and 3% of methanol. Detection takes place at 260 nm. Spectrophotometric analysis consists in the measurement of plasma absorbance at 805 nm. Correlation of both methods is linear r = 0.989, n = 20, p less than 0.05. From the curves of elimination of the dye from the blood bed the principal pharmacokinetic parameters were calculated by means of a one-compartmental model after single intravascular administration. In spectrophotometric examination, elimination of ICG seems to be slower as compared with HPLC.

Chromatography, High Pressure Liquid↗
PubMed1989

[Determination of paracetamol in the blood using high-performance liquid chromatography].

The paper reports the determination of paracetamol in the serum by means of high-performance liquid chromatography. Prior to analysis, the sample is purified by deproteination with perchloric acid. The analysis is carried out isocratically on the reverse phase (SEPARON SIX C18, 5 microns, 150 x x 3.7 mm). The mobile phase consists of 40% methanol in 0.4% phosphoric acid. The detection is performed at 254 nm. The calibration curve is linear in the region 6.62-331 mumol.l-1 (1.0-50.0 micrograms.ml-1) with 95% reproducibility. The sensitivity of detection is 1.3 mumol.l-1 (0.2 microgram.ml-1). The suitability of the method was checked by processing 300 serum samples.

Acetaminophen↗
PubMed1988

The effect of guaiphenesin on absorption and bioavailability of paracetamol from composite analgesic preparations.

Using a one compartment pharmacokinetic model with constant rate of availability for absorption, the disposition of paracetamol was compared after administration of Paralen (paracetamol 500 mg in one tablet) with data obtained after administration of two composite analgesic preparations: Guajanal (paracetamol 500 mg, guaiphenesin 200 mg) and Ataralgin (paracetamol 500 mg, guaiphenesin 130 mg, caffeine 70 mg). The combination of paracetamol with guaiphenesin significantly increased the rate of paracetamol absorption availability, most probably by accelerating its transfer from the stomach to the small intestine. The combination with guaiphenesin and caffeine slightly reduced the rate of paracetamol absorption availability but the difference was not statistically significant. The relative bioavailability of paracetamol from the composite analgesic preparations, however, did not show a statistically significant difference as compared to the preparation where paracetamol was present as a single component.

Acetaminophen↗